Image Processing Reference
In-Depth Information
to the other two components considered. The influence on presence of other screen
variables as the frame rate has been shown in works as [
66
,
67
].
As regards to the influence of auditory features, the audio quality, a realistic
aural rendering of events, and the presence of auditory cues are considered to have a
significant impact on the sense of presence [
14
,
48
,
60
]. The influence of realistic
aural rendering, measured in terms of the number of audio channels (mono, stereo,
and six-channel reproduction), on presence, emotional response and emotion rec-
ognition is analyzed in [
14
]. Stereo and six-channel reproduction had a significantly
stronger impact in emotional response than the mono condition. Similarly,
six-channel reproduction resulted in the highest ratings of presence and emotional
realism. In coherence, an enhanced sense of presence and QoE are reported in [
60
]
and [
68
] respectively, in response to the addition of spatialized audio. In [
48
], the
relative influence of image quality (high definition vs. standard definition) and
sound quality (Dolby 5.1 surround sound vs. Dolby stereo) on presence and
enjoyment is studied. No significant effects of image quality were found. In
contrast, the impact of sound quality on presence and enjoyment was shown to be
significant. Furthermore, a significant cross-modal influence of audio on visual
quality and vice versa has been reported in [
69
], although video quality seemed
to dominate the overall perceived audiovisual quality in the context of the study.
The introduction of interaction has been also found to be significant [
65
]. In
particular, interactions entailing natural physical movements—e.g., head move-
ment [
60
] or walking in place [
70
]—and leading to a coherent system response
(as regards to the individual
s expectations) have shown a great impact on presence.
Likewise, a significant influence of passive haptic feedback on presence has been
reported in [
67
].
Less traditional stimuli as wind, vibration, and light effects have also shown a
significant impact on the user experience (both in terms of enjoyment [
71
] and
QoE), in particular with genres as action movies, sports, news, documentary, and
commercials [
72
]. Likewise, olfactory effects have shown a positive influence on
the perceived quality, relevance, and reality and on the reported enjoyment of a
multimedia experience [
73
-
75
]. A potential exception to these positive effects may
be given by synchronization errors producing a mismatch between video + audio
and olfaction that is outside the temporal range of
'
30s (olfaction ahead of video
+ audio) to +20s (video + audio ahead of olfaction) [
73
]. However, in the case of
video without audio,
the tolerance to synchronization errors with olfaction
decreases [
74
].
Technological breakdowns significantly reduce the potential of mediated envi-
ronments to elicit presence and emotions [
76
]. For instance, an asynchronous
reproduction of audio and video in the context of an audiovisual experience has
shown a negative impact on the clarity of the message, distracting the viewer from
the intended content [
28
]. In particular, users are more sensitive and report higher
annoying effects in the case of audio-led asynchrony [
77
,
78
]. Concerning stereos-
copy, the variables influencing visual comfort in a negative fashion can be classified
as: those introducing spatial distortions as shifts, magnification, rotation, and
keystone; those leading to photometric asymmetries as luminance, color, contrast,
